1. Field of the Invention
The present invention relates to a transmitting apparatus and method, a receiving apparatus and method, and a providing medium. More particularly, the present invention relates to a transmitting apparatus and method, a receiving apparatus and method, and a providing medium which are suitably used, for example, in the case of encoding and transmitting digital signals such as digital audio signals of multiple channels, and receiving and decoding the digital signals to reproduce them in real time on the receiving side.
2. Description of the Related Art
For example, when digital signals such as digital audio signals are transmitted from the transmitting side to the receiving side via a network, e.g., Internet, it is customary that the audio signals are highly efficiently encoded into about 1/10 to 1/100 of original data on the transmitting side, and resulting coded data is transmitted to the receiving side where the coded data is decoded to reproduce the original data.
Generally, audio signals provided via a network are monaural or stereo, and are in a state where sounds of a plurality of musical instruments and a singing voice (words) are mixed with one another. On the receiving side, therefore, a volume level of the entire sounds can be adjusted to increase or decrease, but it is difficult to adjust a volume level of the sound of certain one musical instrument or the singing voice.
However, there is a demand for providing service with high user interactivity (i.e, providing highly versatile audio signals) that enables users on the receiving side to adjust a volume level of the sound of certain one musical instrument or the singing voice, listen to only a vocal apart or an accompaniment part, or listen to the sounds of several desired musical instruments in a mixed state.
To satisfy such a demand, audio signals representing the sounds of a plurality of musical instruments, an audio signal representing the singing voice, etc. require to be transmitted separately without being mixed together. When transmitting a plurality of audio signals separately, the amount of data transmitted to the receiving side is increased in comparison with the case of transmitting those audio signals in a mixed state. For suppressing such an increase in data amount, the amount of data for each of the plurality of audio signals must be reduced. This necessarily results in deterioration of sound quality of the audio signals reproduced on the receiving side.
On the other hand, a transmission rate (usable band) of a network varies depending on the line that is employed by a user for connection to the network, the number of users accessing the transmitting side such as a server, etc. In the case of receiving coded data of a plurality of audio signals, decoding the coded data and reproducing the audio signals in real time on the receiving side, therefore, it may become difficult to decode and reproduce the audio signals in real time because transmission of the coded data is relatively delayed due to the limited transmission rate of the network.
The present invention has been made in view of the state of art set forth above, and intends to transmit a plurality of highly versatile audio signals in an adaptable manner from the transmitting side so that the audio signals are decoded and reproduced in real time on the receiving side.
According to a first aspect of the present invention, in a transmitting apparatus for transmitting coded data resulted from encoding digital signals of multiple channels for each channel, the apparatus comprises dividing means for dividing each of the digital signals of multiple channels into one or more fragments, coding means for encoding respectively the fragments of multiple channels into coded fragment data, selecting means for selecting one of the coded fragment data of multiple channels at the predetermined time, and transmitting means for transmitting the coded fragment data selected by the selecting means.
According to a second aspect of the present invention, in a transmitting method for transmitting coded data resulted from encoding digital signals of multiple channels for each channel, the method comprises a dividing step of dividing each of the digital signals of multiple channels into one or more fragments, a coding step of encoding respectively the fragments of multiple channels into coded fragment data, a selecting step of selecting one of the coded fragment data of multiple channels at the predetermined time, and a transmitting step of transmitting the coded fragment data selected by the selecting step.
According to a third aspect of the present invention, in a providing medium for providing a computer program for rendering a computer to execute a process of transmitting coded data resulted from encoding digital signals of multiple channels for each channel, the computer program includes a dividing step of dividing each of the digital signals of multiple channels into one or more fragments, a coding step of encoding each of the fragments of multiple channels into coded fragment data, a selecting step of selecting one of the coded fragment data of multiple channels at the predetermined time, and a transmitting step of transmitting the coded fragment data selected by the selecting step.
According to a fourth aspect of the present invention, in a providing medium for providing coded data resulted from encoding digital signals of multiple channels for each channel, wherein the medium provides coded fragment data that is obtained by dividing each of the digital signals of multiple channels into one or more fragments, encoding respectively the fragments of multiple channels into coded fragment data, and selecting and outputting one of the coded fragment data of multiple channels at the predetermined time.
According to a fifth aspect of the present invention, in a receiving apparatus for receiving coded data resulted from encoding digital signals of multiple channels for each channel, the apparatus comprises receiving means for receiving the coded data, separating means for separating each of the coded data into coded fragment data that has been resulted from dividing each of the digital signals of multiple channels into one or more fragments and encoding each of the fragments into the coded fragment data, and time information related to the reproduction start time when reproduction of the coded fragment data is to be started, decoding means for decoding the coded fragment data into the fragment, and control means for controlling reproduction of the fragment outputted from the decoding means in accordance with the time information.
According to a sixth aspect of the present invention, in a receiving method for receiving coded data resulted from encoding digital signals of multiple channels for each channel, the method comprises a receiving step of receiving the coded data, a separating step of separating each of the coded data into coded fragment data that has been resulted from dividing the digital signals of multiple channels into one or more fragments and encoding each of the fragments into the coded fragment data, and time information related to the reproduction start time when reproduction of the coded fragment data is to be started, a decoding step of decoding the coded fragment data into the fragment, and a control step of controlling reproduction of the fragment obtained in the decoding step in accordance with the time information.
According to a seventh aspect of the present invention, in a providing medium for providing a computer program for rendering a computer to execute a process of receiving coded data resulted from encoding digital signals of multiple channels for each channel, the computer program included a receiving step of receiving the coded data, a separating step of separating each of the coded data into coded fragment data that has been resulted from dividing the digital signals of multiple channels into one or more fragments and encoding each of the fragments into the coded fragment data, and time information related to the reproduction start time when reproduction of the coded fragment data is to be started, a decoding step of decoding the coded fragment data into the fragment, and a control step of controlling reproduction of the fragment obtained from the decoding step in accordance with the time information.
According to an eighth aspect of the present invention, in a receiving apparatus for receiving coded data resulted from encoding digital signals of multiple channels for each channel, the apparatus comprises receiving means for receiving coded fragment data that is obtained by dividing each of the digital signals of multiple channels into one or more fragments, encoding respectively the fragments of multiple channels into coded fragment data, and selecting and transmitting one of the coded fragment data of multiple channels at the predetermined time; and decoding means for decoding the coded fragment data received by the receiving means into the fragment.
According to a ninth aspect of the present invention, in a receiving method for receiving coded data resulted from encoding digital signals of multiple channels for each channel, the method comprises a receiving step of receiving coded fragment data that is obtained by dividing each of the digital signals of multiple channels into one or more fragments, encoding respectively the fragments of multiple channels into coded fragment data, and selecting and transmitting one of the coded fragment data of multiple channels at the predetermined time; and a decoding step of decoding the coded fragment data received by the receiving means into the fragment.
According to a tenth first aspect of the present invention, in a providing medium for providing a computer program for rendering a computer to execute a process of receiving coded data resulted from encoding digital signals of multiple channels for each channel, the computer program includes a receiving step of receiving coded fragment data that is obtained by dividing each of the digital signals of multiple channels into one or more fragments, encoding respectively the fragments of multiple channels into coded fragment data, and selecting and transmitting one of the coded fragment data of multiple channels at the predetermined time; and a decoding step of decoding the coded fragment data received by the receiving means into the fragment.